Electrical switching mechanism

ABSTRACT

A versatile single pole, double throw switching mechanism is provided with two removable terminal connections to upper and lower stationary contacts. Either contact with its terminal connector may be removed and replaced by an electrically isolated &#39;&#39;&#39;&#39;dead&#39;&#39;&#39;&#39; stop member to produce a single pole, single throw switching mechanism. The vacancy produced by such removal may be covered by a cover plate. One of the stationary contacts is adjustable by a screw member. A cam member adjusts the flexing of the snap blade. Another screw member adjusts the bias of the actuator blade. Two or more switching mechanisms may be unitarily mounted side by side. The casing may be formed by two abutting casing cups. Barbed switch members hold the cup members together. A flat actuating plunger has dirt removing recesses.

United States Patent [72] Inventor [21 Appl. No. [221 Filed [45] Patented [73] Assignee Arthur L. Good Elkhart, Ind.

Dec. 5, 1968 Apr. 27, 1971 Robertshaw Controls Company Richmond, Va.

[54] ELECTRICAL SWITCHING MECHANISM 3,377,450 4/1968 Grady, Jr. et al. ..2O0/I68(A)(X) 3,389,361 6/1968 Manecke 337/347 3,395,375 7/1968 Risk et al. 337/347(X) Primary Examiner-41. 0. Jones Attorney -Candor, Candor & Tassone ABSTRACT: A versatile single pole, double throw switching mechanism is provided with two removable terminal connections to upper and lower stationary contacts. Either contact with its terminal connector may be removed and replaced by an electrically isolated dead" stop member to produce a single pole, single throw switching mechanism. The vacancy produced by such removal may be covered by a cover plate. One of the stationary contacts is adjustable by a screw member. A cam member adjusts the flexing of the snap blade. Another screw member adjusts the bias of the actuator blade. Two or more switching mechanisms may be unitarily mounted side by side. The casing may be formed by two abutting casing cups. Barbed switch members hold the cup members together. A flat actuating plunger has dirt removing recesses.

82 I 2698 llO I l 50 H2 ll l 48 1|91- 4 4 I l i' 86 l 1 so 33 8 9O 0 62 4244i 0 52 I 56 156 t x on 1.1 ol I 58 0e Q ll 56 I y l I '34 I42 104 108 mg l 63 6 Patented April 27, 1971 11 Sheets-Sheet l INVENTOR. ARTHUR L. GOOD BY I I a HIS ATTORNEYS Patntd April 27, 1911 11 Sheets-Sheet 2 GOOD 20 FIG-6 INVENTOR ARTHUR FIG-5 ,6. '2

I34 8+T s l4 HIS ATTORNEYS 4 I Patented ;April 27, 1971 3,576,416

11 Sheets-Sheet 3 96 34 3 FIG-7 ,72 70 I02 a l F 34 FIG-8 26 I34 INVENTOR.

ARTHUR L. GOOD HIS ATTORNEYS Patented April 27, 1911 3,576,416

11 Sheets-Sheet 4 I20" INVENTOR. ARTHUR L. GOOD HIS ATTORNEYS Patented A ril 27, 1911 3,576,416

11 Sheets-Sheet 5 I94 I I FIG-I4 46 20B 246 FIG-l6 246 8O 2 1 74B 22B 61 7 56 17 226" %m I In:

HIS ATTORNEYS 151mg April 27, 1971 3,576,416

11 Sheets-Sheet 6 FIG-35f INVENTOR. 24 ARTHUR L. 6000 250 HIS ATTORNEYS Patented April 27, 1971 3,576,416

11 Sheets-Sheet 1o F IG-33 U G ll FIG-34 28D l22C f ARTHURINLY 52% 276 BY HIS ATTORNEYS ELECTRICAL SWITCHING MECHANISM This invention relates to an electrical switching mechanism.

One of the features of this invention includes a switching construction in which either or both of two opposite cupshaped switch casing cups or blocks receive switch parts during assembly and then the rims of such casing cups are pressed together and are locked together by one or more oppositely directed barbed tooth pieces that enter and produce barbed locks in slots of passageways in the walls of the cups.

Another feature of this invention includes a switching construction having a relatively flat actuator plunger which reciprocates in a relatively flat actuator plunger passageway in the switch casing with longitudinal open clearances for minimizing the effects of dirt particles.

Another feature of this invention includes a switching construction with a reciprocating snap blade with a common terminal and opposite stationary blade stops engaged by said blade and selectively connectable to stationary contact electrical terminals or changeable to electrically isolated stops.

Another feature of this invention includes a switching construction according to the next preceding feature in which an 4 adjusting screw engages and flexes the stationary end of an actuator blade, and another adjusting screw engages one of said stationary contacts.

Another feature of this invention includes a switching construction which can be used as a single unit to control operation of the fan and to limit the burner operation, or two similar switching constructions may be used as dual controls, one to control the operation of the fan and the other to limit the operation of the burner, or for a similar circuit.

Another feature of this invention includes a switching construction according to the next preceding feature in which the dual controls may be secured together to produce unitary construction. 7

Another feature of this invention includes a switching construction in which a central casing cylinder has two end rims which abut two cup rims to produce a casing to encase two unitarily held switches, one of said switches to act as a fan control and the other of said switches to act as a burner limit switch, or for similar purposes.

Another feature of this invention includes electrical terminal replacing or substitute means or plates to replace electrical terminals where such terminals are not to be used, and such plates may have barbed tooth edge constructions to keep them in place or to lock together the two casing cups.

Another feature includes insulative covers for vacancies produced by omission of electrical terminals.

Other features are apparent from this description, the appended claimed subject matter and/or the accompanying drawings, in which:

FIG. I is a diagrammatic showing of two controllers each containing an electrical switching mechanism of this invention, such controllers controlling respectively the operation of a fan and the limit of operation of a burner in response to bonnet temperatures in an air heating furnace.

FIG. 2 is a perspective view of an electrical switching mechanism according to this invention.

FIG. 3 is a perspective view of the mechanism of FIG. 2 but viewed from the opposite comer.

FIG. 4 is an enlarged diagrammatic view of the interior of one of the controllers shown in FIG. 1.

FIG. 5 is a top plan view of one of the sides of the mechanism shown in FIGS. 2 and 3.

FIG. 6 is a side view of FIG. 5 taken from the line 6-6 of FIG. 5.

FIG. 7 is an enlarged view taken along the line 7-7 of FIG. 5.

' FIG. 8 is an enlarged cross section along the line 8-8 of FIG. 5.

FIG. 9 is a cross section along the line 9-9 of FIG. 5.

FIG. 10 is an exploded perspective view of the switch parts mounted on or within the switch casing of the mechanism shown in FIGS. 2 and 3.

FIG. II is an enlarged plan view of the stationary contact holding plate shown in FIG. 10.

FIG. 12 is an enlarged view similar to FIG. 11 but showing the snap blade holding plate of FIG. I0.

FIG. 13 is a wiring diagram showing the connection of the wiring diagram shown in FIG. I to the terminal connectors of the two switching mechanisms contained in the two controllers shown in FIG. I.

FIG. I4 is a wiring diagram somewhat similar to FIG. 13 but showing the control of the fan and the burner of the furnace by a single switching mechanism.

FIG. 15 is a plan view of a dead stop plate to be substituted for the stationary contact holder of FIG. I0.

FIG. 16 is a plan view of two modified switching mechanisms unitarily secured together.

FIG. 17 is an enlarged diagrammatic cross section along the line I7-I7 of FIG. 16, but without background immaterial to the detail shown.

FIG. 18 is a view similar to the upper part of FIG. 7 but showing the modified tenninal constructions of FIGS. I6 and 17.

FIG. I9 is a perspective view of the snap blade holder and terminal connector of FIG. I7.

FIG. 20 is a view similar to FIG. 19 but showing a lower stationary contact and terminal connector of FIG. 16.

FIG. 21 is a perspective view showing part of the terminal connector for one of the upper stationary contacts of the embodiment shown in FIG. I6.

FIG. 22 is a plan view similar to FIG. 5 but showing the switching mechanism modified to have a lower conductive stationary contact and an electrically isolated upper stationary stop, and with a cover plate for the omitted temiinal conductor.

FIG. 23 is vertical side view along the line 23-23 of FIG. 22.

FIG. 24 is a transverse cross section along the line 24-24 of FIG. 22.

FIG. 25 is a view showing a central electrical connection modified from that shown in FIG. 23.

FIG. 26 is a view similar to FIG. 22 but showing the switching mechanism modified to have an upper conductive stationary contact and an electrically isolated lower stationary stop, and with a cover plate for the omitted tenninal conductor.

FIG. 27 is a view along line 27-27 of FIG. 26.

FIG. 23 is a top view of a covering plate to be used to cover the vacancy produced by the omission of terminal conductor of FIG. 26.

FIG. 29 is a cross section along the line 29-29 of FIG. 28.

FIG. 30 is a top plan view of an embodiment of two casing cups with rims respectively engaging the end rims of a central short rectangular cylinder.

FIG. 31 is a cross section along line 311-311 of FIG. 30.

FIG. 32 is a cross section along line 32-32 of FIG. 30.

FIG. 33 is a cross section along line 33-33 of FIG. 30.

FIG. 34 is a cross section along line 34-34 of FIG. 30.

FIG. 35 is a top view of a plunger receiving opening with one half of the plunger illustrated and one half omitted taken along the line 35 of FIG. 7.

FIG. 36 is a top view of a plunger that may be used in the opening of FIG. 35.

FIG. 37 is a bottom view of the plunger.

FIGS. 38 and 39 are side views of the plunger.

FIG. 40 is a cross section along line 40-40 of FIG. 27.

FIG. 41 is a view showing the parts of FIG. 40 in locked position.

FIGS. 42, 43 and 44 are views respectively similar to FIGS. 16, I7 and 13, but showing another embodiment.

FIG. 45 is a perspective view of one of the connectors of FIGS. 42-44.

FIG. 46 is a view similar to FIG. 44, partly in elevation, and showing another embodiment.

FIG. 47 is a cross section of a modified rim construction between abutting casing members.

Certain words are used in this application that indicate direction, relative position and the like of the parts being described. Such words are used for the sake of brevity and cleamcss. These words are used only in connection with appropriate views of the drawings. in actual use, such parts so described may have entirely different direction, relative posi tion and the like. Examples of such words are vertical," horimntal," "upper," "lower," and the like.

An electrical switching mechanism 20, according to this invention, is a versatile mechanism. It is useable anywhere that a single pole, double throw switch may be used. Also, this mechanism may be modified or adjusted to provide switching mechanism adapted for use in many different arrangements. whether the various switching mechanisms that are produced are used as double throw switches, or as single throw switches. This versatility will become apparent, as the description proceeds.

The electrical switching mechanism may have an insulative switch casing 22 which may have a bottom wall 24, longitudinal sidewalls 26 and 28, transverse end walls 30, 32 and a cover wall 34. These walls surround a switch cavity 36, within which a plurality of switch members, to be described, produce a switch that may be a single pole, double throw switcn, anu which may be adjusted very simply and effectively, to produce circuit controls of wide variety, including single pole, single throw switches.

Upper and lower stationary blade stop members 38 and 40, FIG. 7, may be placed at one end of the relatively long and narrow switch cavity 36. A snap blade holding stationary member 42 may be placed at the other end of the cavity 36. The member 42 may hold the stationary end 44 of a snap blade 46 which extends along the cavity 36 and has a snap end 48, which may have movable contacts 50 and 52 movable between the stationary stop members or stationary contacts 38 and 40.

A gradually movable actuating blade 54 has one end 56 stationarily pivoted at the other end of the cavity 36, in notch 58 in the casing 22. The actuating blade 54 extends along the cavity 36 and has a free end 60 adjacent the snap end 48 of the snap blade 46.

Snap producing means 62, in the fonn of a C spring, is placed at the free end 60 and the snap end 48 of the blades 54 and 46, and causes a snap movement of the snap end 48 of the snap blade 46, and its contacts 50 and 52, as the actuating blade 54 is gradually moved back and forth.

Thus a snap blade construction has been provided which is held at one cavity end by the stationary blade holding member 42, with such snap blade construction having a snap end 48 at the other cavity end. The snap end 48 snaps between the stationary stop members 38 and 40.

A gradually and vertically movable actuator 63 is actuatable from the outside of the switch casing 22, such as by the sensor arm 64 and the compression spring 66, thus gradually moving an intermediate part of the actuating blade 46 at the contact 68. However, the actuator 63 is nonconductive, and may be made of plastic material, so that there is no electrical conduction at 68.

A first electrical terminal construction 70 extends from the snap blade holding stationary member 42 to the outside of the casing 22 and may be provided with any suitable terminal securing means, such as the screw 72.

A second electrical terminal construction 74, FIG. 8, extends from the lower stationary stop member or contact 40 to the outside of the switch casing 22. Such second terminal construction may be provided with a wire terminal connector means or screw 76.

A third electrical terminal construction 78, FIG. 7, may extend from the upper stationary stop member 38 to the outside of the switch casing 22, where a wire terminal connector or screw 80 may be provided.

A first manual insulative vertical adjusting member 82 may be carried at one end of the switch casing 22 to adjust one of the stationary stop members, such as stationary stop member 38.

A second insulative manual adjustment member 84 may be carried at the other end of the switch casing 22 adjustably to impart a downward bias on an intermediate portion 86 of the gradually movable blade 54 against the upward movement of the actuator or plunger 63.

The first and second manual vertical adjusting members 82 and 84 may be insulative screw constructions, having threads 88 and 90, which engage respectively threads 92 and 94 in suitable openings of the casing 22 to cause these screw members 82 and 84 to move upwardly and downwardly, when they are rotated, for example, by the screwdriver receiving slots 96, 98 on top of the switch casing 22.

The first and second electrical terminal constructions 70 and 74, FIGS. 7 and 9, extend transversely of the length of the switch casing 22 and the third electrical terminal construction 78, FIG. 7, extends longitudinally of the length of the casing 22.

Each of the electrical terminal constructions 72, 74, and 78 includes electrically conductive ribbons extending out of the switch casing 22. The third electrical terminal construction 78 includes a relatively flexible electrically conductive ribbon 100, FIG. 7, which is connected to the stationary stop member 38 at one end and to another relatively stiff electrically conductive ribbon 102 extending out of the switch casing 22, and to which the screw is attached.

A third manual adjusting member 104, FIGS. 7 and 10, imparts an upward bias on an intermediate portion of the blade 46. Such third manual member 104 may include two rotatable cam members 106 which are mounted on the shaft 104, which shaft extends out of the switch casing 22 at the rectangular extension 108, which may be manually adjusted by lever 110 outside the casing 22.

The snap blade 46 may preferably be made of two downwardly biased ribbons 112 which are attached to the snap blade holding member 42 at one end, and are united at the bridging member or snap end 48 which carries the upper movable contact 50, and lower movable contact 52. The bridging member 48 may have a tongue 116 which receives openings 118 in the C spring 62, which C spring also receives a tongue 119 ofthe blade 54.

The foregoing switch producing members inside of the cavity 36 may be varied, omitted, and replaced, for the adjustment alteration of the switching mechanism for various usages, as will become apparent.

The electrical switching construction 20 may be formed by and may include an insulative switch casing 22. Such casing 22 may be formed by and may include two insulative cups 120 and 122, aptly illustrated in FIG. 8. These cups 120 and 122 have adjoining and abutting rims 124 and 126. The cups also have cup bottoms 26 and 28 which are also frequently identified as longitudinal casing sidewalls 26 and 28. The cups also have adjoining cup sides 132 and 134, identified in FIGS. 2, 3, and 8, which, when united, form casing end wall 30. The cups also have cup sides 136 and 138, identified in FIG. 5 which, when united, form casing end wall 32. The cups also have lower cup sides 14-0 and 142, as shown and identified in FIG. 8, which when united, form casing bottom wall 24. The cups also have upper cup sides 144 and 146 as shown and identified in FIG. 8 which, when joined together, form the easing cover wall 34.

For convenience, the casing cups 120 and 122 will be occasionally referred to as the near casing cup 120 and the far casing cup 122, because they are frequently so viewed in FIGS. 2, 5, etc.

The casing cups 120 and 122 are held together by barbed members or barbed saw-toothed members 148 and 150 of the stationary contact carrying plate 156, FIG. 11, and by barbed members 152, 154 of snap blade holding member 42, FIG. 12. These barbed members bite into the sides of notches in the casing 22 which are located in opposed casing cups 120 and 122 to hold such cups together after they have been forced toward each other.

Certain of the switch parts may be first assembled in proper notches of one or both of the casing cups 120, 122 while such cups are separate from each other, as diagrammatically indicated by dotted lines in FIG. 3. When the cups 120 and 122 are forced or assembled together so that such switch parts are held within the assembled casing 22. The rims 124 and 126 of the cups 120 and 122 are abutted and assembled together, as shown in FIG. 8, for example. The cups are locked together by the locking action of the barbed members 148, 150, 152, and 154 when these barbed members are inserted in the slots in opposed cups 120 and 122 which receive the respective barbed members, as illustrated in FIGS. 11 and 12.

The plates 156 and 42 of FIGS. 11 and 12 are part of the electrical terminal constructions 74 and 70. The barbed members 148, I50, 152, and 154 and the plates 156 and 42 engage the opposite cups 120 and 122 with a holding action as shown in FIGS. 11 and 12.

The construction of the barbed members 148, 150, 152, 154 illustrates that any desired switch forming parts can be placed in the cavity 36 and can be attached to both of the other of the cups 120 and 122 with some of the barbed members in one cup and other barbed members in the other cup.

The electrical switching mechanism 20 may have its actuator 63 actuated by any type of sensor, such as the rod and tube thermally responsive sensor 160 of FIG. 4. Such sensor may have, for example, a brass tube 162 and a steel rod 164. The brass tube 162 may be secured to a wall 166 of a controller casing 168 in which a switching mechanism 20 is supported by brackets 170. The steel rod 164 may be connected to a pivoted lever 64, which is fulcrumed at 174 on a bracket 176, carried by the wall 166. The steel rod 164 passes through the lever 64 and may be held by an adjusting nut 178 threaded on the screw end 180. As the steel rod expands at a greater coefficient of expansion than the brass tube 162. a heating action causes the rod 164 to pull the lever 64 leftwardly against the compression spring 66. This allows the actuator 63 to move leftwardly as viewed in FIG. 4 from the switching mechanism 20 with a rise of temperature in the space in which the rod and tube sensor is located. This causes the switching mechanism 20 to be responsive to air temperatures adjacent the switching mechanism 20, and the casing 168 in which it is located.

Therefore, the switch construction 20 may be used in any location where a sensor may be provided which is responsive to temperature. It is to be understood, however, that any other type of sensor or actuating mechanism may be used instead of the rod and tube 160, and that the sensor may be responsive to other things than temperature such as pressure and the like.

An example of the use of one or more of the switching mechanism or mechanisms 20 is shown in FIGS. 1 and 13. For example, a furnace 182 may have a burner 184 and a fan 186 operated by an electric motor 188. A gas supply pipe 190 may be connected to the burner 184 under the control of any one or more valves 191, 192 and 193 and a solenoid valve 194. These valves control the operation of the burner 184, and of the pilot 196. The air is heated by the burner and is delivered by the fan 186 through air ducts 196 and 197 to the area 108 to be heated and controlled. A fan operation controller 200 (such as shown in FIG. 4) may control the operation of the fan motor and fan in response to air temperatures in the bonnet of the furnace and in response to controlling operations of the sensor 202. The controller 200 will start the fan motor and fan when a comfort producing temperature is created in the furnaee bonnet and will stop the fan when the air temperature has reached a temperature that will produce discomfort. A burner controller 204 with a burner limit sensor 206 controls the operation of the solenoid valve 194 to cut 011' the gas to the burner 184 when the temperature in the bonnet of the furnace 182 rises above a desired limit temperature. The burner limit controller 204 causes the solenoid valve 194 to cut off the gas to the burner 184 when the bonnet temperature of the furnace 182 reaches a limiting temperature above which it is not desired to operate the burner 184. As long as the temperature of the bonnet 182 is below its iimiting temperature, the burner 184 can be controlled by a wall or room thermostat 208. The wall thermostat will cycle the burner in response to air temperatures in the room or space 198 to cause the furnace to maintain the room temperature within the differential tem' peratures of the wall thermostat 208, as long as the burner operation is not stopped by the limit controller 204.

The fan and burner limit controllers 200 and 204 may be similar to that shown in FIG. 4, and the switching construction in the controllers 200 and 204 may be substantially as shown in FIGS. 212.

FIG. 13 shows a wiring diagram having the same results as the wiring diagram shown in FIG. 1. However, FIG. 13 additionally shows how the power lines, etc. may be connected to the contacts of the respective switching mechanisms in the controllers 200 and 204. However, it is to be understood that the operativeness of the switching constructions of FIGS. 2- 12 is not dependent on the operativeness of the disclosures of FIGS. 1, 13, and 14 since such switching constructions may be used for any purpose independent of the disclosure of FIGS. 1, 13, and 14.

The switching mechanisms 20 in the controllers 200 and 204 may be identical to the switching constructions shown in FIGS. 212 with all terminal connector parts 72, 76, and 78 made available if desired, but not always used. That is, the switching mechanism 20 in controller 200 will utilize only the fan connector and the snap blade connector 72. The terminal connector 76 is not used and will not be connected to any electrical line. On the other hand, if desired, the burner limit terminal construction 74, 76, and 156 may be omitted from the switching mechanism 20 of fan controller 200 and a substitute electrically isolated or dead" stop member 210 may be substituted therefor. The vacancy produced by the omission of terminal connector '76 may be covered by a clip 212 as shown in FIGS. 22-24, as will be elsewhere described.

Likewise, the switching mechanism 20 in burner limit controller 204 utilizes only terminal connectors 72 and 76, and the fan tenninal connector 80 may be omitted and may be covered by a covering slip 212 as shown in FIGS. 26 and 27, to be later described.

It is thus to be seen that the switching construction 20 shown in FIGS. 2-12 may be used as a double throw switching mechanism which utilizes all of the terminal connectors 72, 76, and 80, or it may be used as a single throw switching mechanism by not connecting either terminal connector 76 or terminal connector 80 or by further modifying the switching mechanism by substituting the substitute connector parts and cover 212 or the omitted connector 76, or the covering 212 and substituted parts for the connector 80, as will become further apparent.

Reverting to FIGS. 1 and 13, it is to be seen that the fan controller 200 may have its connector 72 connected to line L and its connector '76 connected to the fan motor 188. When the sensor 202 is heated by bonnet temperature at or above the desired starting temperature, the connector 76 will be electrically energized and electric current may be sent to the fan motor 188 and from thence to the line L. The burner limit controller 204 may be connected to a low voltage circuit of 24 volts, for example, which is produced by the transformer 214 from lines L. L wherein the low voltage coil 216 establishes a circuit which goes through the wall thermostat 208 then to the terminal 72 and through the switching mechanism to the terminal 76. If the temperature in the bonnet rises above the desired limit the limit sensor 206 causes the movable contact 82 to engage the stationary contact 40 thus electrically energize the terminal 76 and energize the relay coil 218 and close the bridging contact 220 of the relay 222. This causes the-coil 224 of the gas valve 194 to be energized across L', L to close valve 104 and to turn off the gas to the burner 184. The burner will remain turned off until such time as the bonnet temperature falls below the safe limit established by the temperature sensor 206. As long as the bonnet temperature is below the safe limit temperature, the contact 40 and the relay coil 218 are not energized, and the condition. of the circuit as illustrated in FIG. 13 is maintained with the contact 40 not energized and thus the relay contact not closed and the gas valve 194 remaining open to allow control of the burner by the wall thermostat 2013.

The circuit of FIGS. 1 and 13 shows that the switching mechanism 20 may be used as a fan controlling mechanism and as a burner limit switching mechanism.

It is thus to be seen that the switching mechanism 20 of this invention may be used in a versatile manner not only as a fan control or a burner control but also for any other conditions of circuits desired.

The switching mechanism 20 shown in FIGS. 2-12 may be also used to control the fan or the burner of a furnace, if desired, without using two switching mechanisms 20. This is shown in FIG. 14.

A controller 226, FIG. 14, may have a switching mechanism 20 as disclosed in FIGS. 2-12 with the line L passing through a wall thermostat 228 and being connected to terminal connecter 72, with terminal connecter 80 connected to the line 230 leading to the fan motor 232 of a furnace similar to the furnace 182 of FIG. 1. The other side of the fan motor 232 is connected to the electrical line 234, and to the source L A time delay switch 236 is interposed in the line 230 to delay the starting of the fan motor 232 for a substantial period of time. Any tyne of time delay switch may be used. For example, a normally open bimetal blade 238 is heated by a small capacity electric heater 240 which is connected across the lines 230 and 234 and which is heated whenever the terminal connecter is energized by the snap blade 46. However a delay in heating and closing the bimetal blade 237 causes a delay in starting of the fan motor after the connecter 80 is energized. The fan 232 is deenergized when such terminal connecter 80 is deenergized by the downward movement of the blade 46.

The gas burner valve 242 is similar to the valve 194 of FIG. 1 but has a solenoid 244 which turns the gas on when the solenoid 244 is energized when the snap blade 46 is snapped down by the upward movement of the plunger 63, when the sensor 160 is cooled below the set limit. This turns off the fan motor 232 and the burner on until such time as the bonnet temperature heats and again snaps the blade 46 up to energize the line 230 and to cause the burner to be turned off by the snap action. It is thus to be seen, that the single switch of FIGS. 2-12 may be used as a single switch to control both the fan motor and the burner valve, as desired.

The foregoing descriptions concerning the operation of a furnace is made merely to illustrate possible uses of the switching mechanism of FIGS. 212. However, it is to be understood that the switch may be used for many other purposes than the control of a fan and gas valve of a furnace, as is obvious, and such switching mechanism may be used either as a single pole double throw switch, or as a single pole, single throw switch, as desired.

The electrical switching mechanism 20 of FIGS. 1-15 may be slightly modified so that two of such mechanisms can be united side-by-side and secured together as by bolts and the like so that two or more of such switching mechanisms can be merchandised as a single unit to control a plurality of circuits, as may be desired.

For example, in FIGS. 16-21 two such mechanisms 20A and 2013 may be slightly modified and then united as shown in FIG. 16; but may be separated by an insulating sheet 245, if desired. Certain elements of these units will be designated by the same reference numerals as in FIGS. 1-15. However, where they have been modified slightly, then the reference numerals will have the suffixes A or B applied thereto to indicate that there is a slight similarity but a sufficient modification to enable the units to be mounted together.

For example, the casings 22A and 22B are modified to receive modified thick ribbon electrical terminal constructions 70A and 708, 102A and 1028. and 74A and 748. These constructions have been modified by having such relatively thick ribbon terminal constructions extend directly upward through the casings 22A and 228 so that these terminal constructions do not extend sideways to interfere with the side by side unification of the casings 22A and 22B.

The manner in which these terminal constructions 70A and 70B are mounted in the casings 22A and 2213 may be readily understood from FIGS. 17, 18 and 19 wherein the snap blade holding member 42A and the straight terminal construction 70A extend upwardly in a channel 246 which is formed in the cup bottom 28A and 288, as shown in FIGS. 17 and I6. Previously to uniting the mechanisms 20A and 2013, the electrical connecter 70A was a straight line extension of the snap blade holder 42A. as shown in dotted lines in FIG. 19. Such member 70A, while in such straight line condition, was inserted through the bottom 28A where an opening 247 and a suitable notch 249 were provided in the bottom structure 28A to allow the straight part 70A to pass through the bottom 28A and the arms 248 and 250, FIG. 19, to lodge in suitable notches 249 so that the barbed members on arms 248 would bite into the bottom structure 28A. Then the member 70A will be straightened upwardly as shown in full lines in FIG. 19 and FIG. 17, Later when the left segment (in FIG. 17) or cup having the bottom 26A is forced into contact with the right cup, then the arms 253 and 255 will enter a suitable notch 249 in the cup bottom 26A as shown in FIG. 17.

The terminals 74A and 748 will be assembled on the cup bottoms 28A and 28B substantially in the same manner as shown in FIG. 17, except that the plate 156A is lower than the plate 42A, as is evident from a comparison in FIG. 18 of the corresponding plates.

The connecters 102A and 1028 are made by extending the conductor 102A upwardly in FIG. 18, as compared to the previous end shown in FIG. 7, and passing the extension through a slot 251 in the top wall (in FIG. 18) of the casing 20A.

The other members of the switch constructions inside the casings 22A and 22B are shown in FIG. 18, and are repetitions of the parts shown in FIG. 7, wherein many of old switch parts are given the old reference numerals, to identify a sufiicient number of such parts without repeating all of the reference numerals of FIG. 7. Suitable slots are provided in the cup bottoms 26A and 28A and in the cup sides to receive the edges of all of the members that are to be held in the cavity, as is obvious. Aside from causing the terminals 70A, 7013, 74A, 748, 102A and 1028 to pass through the respective top walls of the casings 20A and 208 (as seen in FIGS. 17 and 18) the parts of the mechanism 20A and 208 may be substantially as in FIGS. l-IS.

FIGS. 22-27 are views showing how either of the upper or lower stationary conductive contacts may be changed to nonconductive or dead" stop members to change a standard switching mechanism into various single throw switches. These FIGS. also show how the corresponding electrical terminal connecters may be omitted and the vacancy so produced in the casing may be covered by a cover plate or clip.

FIGS. 22-24 show how the normal or standard lower electrical stationary contact 156 can be omitted and in lieu thereof an electrically isolated or dead" lower stop plate 210 of FIG. 15 may be substituted therefor. This plate 210 may have barbed members 252 and 254, FIG. 15 corresponding to barbed members and of the normal conductive plate 156 for which plate 210 is substituted. The plate 210 may be an electrically conductive metal plate, but it is electrically isolated or dead" by the action of the nonconductive casing 22 which carries it. Additionally the substitute stop plate 210 holds the casing cups 120 and 122 together after they have been abutted and assembled together by reason of the barbed members 252 and 254 of stop plate 210.

The vacancy in the casing 22 produced by the omission of the normal terminal conductor 74 and conductive plate 156 may be covered by a covering plate or clip 212 which may be made to fit sufficiently tightly in the vacancy to prevent its accidental removal, as is now obvious.

The switching mechanism of FIGS. 22-24 can therefore be used only as a single pole single throw switch, and the threaded screw members can be adjusted to regulate the snapping conditions of the snap blade 46 in the previous manner.

FIG. 25 shows an embodiment somewhat similar to that of FIGS. 22-24. However, the normal terminal construction 78 of FIG. 23 has been changed to a terminal construction 256 in which a relatively heavy conductive ribbon 258 has substantially horizontal ends 260 and 262 and an intermediate vertical part 264. The end 260 and a portion of part 264 may be received in suitable notches of the casing cups 120 122 so that the tenninal 258 is securely held in place after the cups have been assembled. The normal adjusting screw 82 may be omitted, and the vacant screw threaded hole 266 in casing' 22 may be covered by an insulative block 268 which may be placed in the cavity 269 which may be provided in the casing cups so that the block 268 can be secured in place when such casing cups are abutted and assembled.

Snap adjustments of the snap blade by the screw 84 and the cam adjusting member 104 shown in FIG. 10, can be used to adjust the snap action of the snap blade 46.

FIGS. 26 and 27 show a normal switch construction in which the normal upper stationary contact is omitted along with its non'nal electrical terminal 78 shown FIG. 23 or other FIGS.

The vacancy produced in the casing 20 by the omission of terminal 78 is covered by a cover plate or clip 212 which is made of the propersiae to fit into the vacated casing cup notches 270, 272 and 274 which were vacated by the omission of the terminal conductor 78 of FIG. 23 and other FIGS. Such clip 212 is secured and locked in place when the casing cups are abutted and assembled.

FIGS. 30-34 show a unitary two switch electrical switching mechanism 20C which has a near casing'cup 120C, a far casing cup 122C and a short intennediate casing rectangular cylinder 276 which has end rims 278 and 280 which can respectively abut with and be secured to the cup rims 124A and 126A of the casing cups 120C and 122C to form a. unitary switching mechanism 20C which contains two parallel switches respectively surrounded by respective abutting cylinder rims 278 and 280.

The near casing cup 120C may be substantially the same as the near casing cup 120 of the previously disclosed near casing pendently snapped by respective gradually actuable plungers 290 and 292 and respective actuating blades 294 and 296 in the same manner as theprevjously described switches.

A second electrical terminal 76D is connected to the lower stationary contact 521), FIG. 34 which is carried by the stathick ribbon 102D of terminal construction 78D, FIG. 32. This construction 78D also carries the relatively thin flexible blade 100D, which carries the adjustable stationary upper contact 38D. The contact 38D is contacted by the movable contact 50D, which is carried by the snap blade 286.

The snap blade 286 is indirectly snapped by the actuating fan plunger 290.

If the switching mechanism 20C is to be used as a furnace controller similar to that shown in FIG. 1, the plunger 290 will be actuated by a fan sensor that is to control the operation of the fan. When such fan sensor senses a comfort producing bonnet temperature the plunger 290 will be moved down the correct amount to snap the blade 286 up to the position of FIG. 32 which will energize the terminal 80D which is connected to the fan. The fan will be operated until stopped when the bonnet temperature cools sufficiently to cause the blade 286 to snap down and open contact 38D and terminal 80D.

Because of the continuous supporting member 284, FIG. 31, the fan circuit and burner circuit will operate on the same voltage with both circuits being on line voltage or with both circuits being on transformer reduced voltage as will be obvious to those skilled in this art from the disclosure herein made.

The other switch parts within the switching mechanism 20C can be made to operate substantially similarly to the previously disclosed parts.

tionary plate and terminal ribbon 156D under snap blade 288,

FIG. 34.

The cup 122C and the cylinder 276 are secured together by barbed structures in plates 156D similar to the barbed structure of plate 156. Suitable slots are provided in intennediate wall 282 and cup bottom 28D, FIG. 34.

If the switching mechanism 20C is to be used as a furnace controller for a furnace similar to that shown in FIG. .1, the thermally responsive sensor which is to limit the operation of the burner will operate the (burner) plunger 292, FIG. 31, to

stop operation of the burner when the furnace bonnet reaches a limit temperature with the same ultimate result as in FIG. I. The limit terminal 76D will be connected to control the gas valve.

A third electrical (fan control) terminal 80D is connected to a transverse conductive plate 298. This plate 298 is made integral with or connected with the original type of relatively The switching mechanism 20C can therefore provide substantially a unitary controller that can control the fan and limit the operation of the burner, or can be used to control any similar operation.

All of the electrical switching mechanisms herein disclosed can be used to control any type of circuit or circuits desired, and they can be, but need not be, furnace control circuits and the like.

Any type of well known longitudinally movable plunger construction may be used to actuate the switches herein disclosed. However, the specific plunger construction disclosed in FIGS. 3539 has advantages that make it desirable to use as herein disclosed.

The plunger 63 may operate in the plunger opening structure 300 which has tapered opening sides 302 and tapered opening ends 304 (FIG. 7). The plunger has tapered plunger sides 306 and tapered opening ends 308 which engage or bottom upon the tapered opening sides 302 and opening ends 304 when the plunger has been allowed to move to its lowest position, as shown in FIG. 7 by the sensor lever 64.

The opening structure also has a relatively straight rectangular upper opening 310, FIG. 7, in which the transverse plunger plate 312 reciprocates as the plunger 63 is reciprocated.

The plate 312 has rounded comers 314 and inward recessed sides 316, which provide recess between the opening sides and the plunger to allow flash and dirt to fall down out of the plunger passageway.

The plunger has a straight sided lower pan 318 which has longitudinal grooves 320 to allow the dirt to fall through the lowest plunger opening 322. This keeps the plunger free from particles that might prevent free travel of the plunger.

The plunger with relatively large width and small thickness is advantageous in keeping a trouble free reciprocation.

FIGS. 40 and 41, along with FIGS. 7, 8, 26 and 27 show the construction of the first and second insulative manual adjusting members 82 and 84 and the cooperation of their threads 88 and 90 with the threads 92 and 94 of the casing when such members are rotated by a screwdriver or the like in the slots 96 and 98. This adjustment may be readily accomplished at the place of installation by anyone familiar with switch constructions of this type.

The insulative members 82 and/or 84 may each be provided with a screw 330 which is adjustably fixed in its respective member 82 and/or 84 by a relatively tight adjustable screw thread engaging arrangement 332, so that the lower end of the screw 330 may extend down below the lower end of the respective member 82 and/or 84. Such screw 330 may be substantially of the same construction where variously illustrated in the drawings. The screw may have a hexagonal slot 334 at its upper end in which a hexagonal screwdriver may be used to adjust the length of exposed screw below the member 82 and/or 84. In the examples generally illustrated only the member 82 has such a screw 330 and the member 84 is not provided with such screw 330, but the lower rim of member 84 engages the intermediate part 86 of the gradually movable blade 54, as illustrated in FIGS. 7 and 10.

The adjustment of the screw 330 in the member 82 (or 84) is intended to be a factory" adjustment or an adjustment to be made by particularly well trained technicians at distribution agencies and the like.

The lower end of screw 330 of the vertical adjusting member 82 may be used as an adjustable stop for the stationary contact 38, as in FIG. 7, or as an insulated stop member for the movable contact 50 of the snap blade 46, as in FIG. 27, for example.

The insulative manual adjusting members 82 and 84 may each have a radial pin 336 or 338 respectively, which may be rotatable in the cavities 269 or 340 respectively when such pins 336 and 338 are placed in the rotatable area of the cavities 269 and 340 respectively. The vertically adjustable members 82 and 84 may therefore be vertically adjusted when the pins 336 and/or 338 are in such rotatable areas of the cavities 269 and/or 340.

The cavities 269 and 340 may have locking notches 342 and 344 respectively, FIGS. 26, 27, 40 and 41, in which the pins 336 and/or 338 may be placed during assembly of the switch, as shown in FIG. 41 for example, to lock the vertically adjustable member 82 (or 84) against field adjustment by the usual service man by use of a screwdriver in the slot 96 or 98. Only factory personnel or a trained technician at the field can make the screw adjustment which can then be generally made by the use of a special thin hexagonal screwdriver extending into the hexagonal slot 334, or similar screw construction in member 84, if provided.

In the construction of FIGS. 42, 43 and 44, one, two, or more switch constructions 350, 352, etc., may be used singly or may be secured side by side similarly to the switch constructions of FIGS. 16, I7 and 18 with one or more insulating sheets 354 between them.

The switch constructions 350 and 352 have been shown as identical to each other as to the arrangement of the parts, but such switch constructions may be individually varied, if desired, to provide, for example, a burner control switch construction, and a fan control switch construction, of the types previously disclosed, and unitarily secured together by screws, bolts and the like, not shown. Such switch constructions 350 and 352 may be provided with mounting screw holes 351 and 353 to mount the plural switch unitary construction, or individual switch construction on a support.

Certain elements of the two switch constructions 350 and 352 will be designated by the same reference numerals as in previous FIGS. However, where they have been modified slightly, then the reference numerals will have the suffix E applied thereto to indicate that there is a slight similarity, but sufficient modification, to enable the units to be mounted together.

One of the features of these embodiments of FIGS. 42-45 is that the thick ribbon electrical terminal constructions 70E, 102E and 74E are mounted transversely to the longitudinal central plane of the switch constructions and along the abutting rims 356 and 358 of the casing cups 360 and 362 of the respective switch constructions 350 and 352.

The abutting cups 360 and 362 may produce an insulative switch casing 22E which may have a bottom wall 24E, longitudinal sidewalls 26E and 28E, transverse end walls 30E and 32E and a cover wall 34E, which surround the switch cavity 36E.

The snap blade holding member 42E, with snap blade ribbons 112E, FIG. 45, and the straight terminal construction 70E previously to a bending operation were in a straight line LII condition, as shown in dotted lines in FIG. 45. However, such terminal construction 70E may be bent to the full line position of FIG. 45 prior to assembly in the cups 360 and 362. The snap holding member 42E has barbed members 152F and l54F, similar to those shown in FIG. 12, and are received in slots 364 in the cup bottoms 26E and 28E in a manner similar to previously disclosed embodiments. The terminal connectors 70E pass through slot constructions 368 in the cup opposed cup rims 356 and 358.

The terminal constructions 102E may be substantially the same as previously described in connection with terminals 102A and 1028 of FIGS. 16, 17 and 18, and pass through passageway constructions 370 in opposed cup rims 356 and 358.

The terminal constructions 74E may be connected to contact plates 156E having barbed members 148E and 150E with the terminal constructions 74E extending longitudinally along the switch constructions 350 and 352 and being bent upwardly at 366 to pass upwardly through passageways 372 in the cover wall 34E.

Each contact plate 156E may have the terminal construction 74E bent and extending upwardly from the plate 156E, in a manner somewhat similar to that shown in FIG. 45, except that the terminal construction 74E is bent at the left hand edge of the plate 156E instead of the right hand edge that is shown in FIG. 45. Also, the contact plate 156E will have one central contact or indentation instead of the two circular attachments shown in FIG. 45. The snap blade ribbons 112E of FIG. 45 will also be omitted.

In the embodiment of FIG. 46, substantially the same construction is used as has been described in connection with FIGS. 42-45. However, the terminal construction 102E has been changed in the same manner as shown in FIG. 25. The other parts of the switch construction remain the same as in FIGS. 42-45. The other terminal constructions 74E and 70E are designated to indicate this identity with FIGS. 42-45.

FIG. 47 shows diagrammatically that the rims 380 and 382 of any of the casing cups herein disclosed may be provided with overlapping portions 384 and 386 in part or substantially all of the perimeters of such rims, if so desired.

A new, useful and unobvious electrical mechanism has thus been provided.

lclaim:

I. In combination:

an insulative switch casing having a bottom wall, longitudinal sidewalls, transverse end walls and a cover wall surrounding a relatively long and narrow switch cavity;

upper and lower stationary blade stop members at one end ofsaid cavity;

a snap blade holding stationary member at the other end of said cavity and holding a stationary end of a snap blade which extends along said cavity and has a snap end between said stationary blade stop members;

a gradually movable actuating blade with one end stationarily pivoted at said other end of said cavity and extending along said cavity with its free end adjacent said snap end of said snap blade;

snap producing means at said free end and snap end of said blades causing a snap movement of said snap blade as said actuating blade free end is gradually moved back and forth;

a vertically movable actuator actuatable from the outside of said cavity gradually moving an intermediate part of said actuating blade;

a first electrical terminal construction extending from said snap blade holding stationary member to the outside of said switch casing;

a second electrical terminal construction extending from said lower stationary stop member to the outside of said switch casing;

a third electrical temrinal construction extending from said upper stationary stop member to the outside of said switch casing;

switching a first manual vertical adjusting member carried at one end of said switch casing vertically to adjust one of said stationary blade stop members;

and a second manual adjusting member carried at the other end of said switch casing adjustably to impart a downward bias of an intennediate portion of said actuating blade against said actuator.

2. A combination according to claim I in which said first and second electrical terminal constructions extend transversely of the length of said switch casing and said third electrical terminal construction extends longitudinally of the length of said switch casing.

3. A combination according to claim 2 in which said electrical terminal constructions each includes an electrically conductivc ribbon extending out of said switch casing.

4. A combination according to claim 3 in which said third electrical terminal construction includes a relatively flexible electrically conductive ribbon connected to said upper stationary stop member at one end and to another relatively stiff electrically conductive ribbon extending out of said switch casing.

5. A combination according to claim 1 in which a third manual adjusting member imparts an upward bias on an intermediate portion of said snap blade.

6. A combination according to claim 5 in which said third manual member is a rotatable cam member which has an extension extending out of said switch casing.

7. A combination according to claim 6 in which the snap blade has two ribbon members and the rotatable member has two cams carried on a shaft and engaging said ribbon membets.

8. A combination according to claim 7 in which said shaft has an extension out of said switch casing and said extension is operated by an adjusting lever.

9. A combination according to claim I in which said switch casing is formed by two insulative easing cups having respective adjoining rims, having cup bottoms forming said longitudinal sidewalls of said switch casing, having certain adjoining cup sides forming said transverse end walls of said switch casing, having other cup sides forming said bottom wall of said switch casing, and having other cup sides forming said cover wall of said switch casing.

10. A combination according to claim 9 in which said cups are held together by barbed members which engage said cups with a holding action.

ll. A combination according to claim 10 in which at least one of said electrical terminal constructions has some of said barbed members.

12. A combination according to claim 9 in which at least one of said terminal constructions includes at least one plate that extends into receiving slots in said cups.

13. A construction according to claim l2 in which at least one of said plates has barbed members which engage said cups with a holding action.

l4. A combination according to claim 9 in which certain of the switch forming parts in said cavity can be first attached to one of said cups and then to the other of said cups.

15. A combination according to claim M in which at least one of said electrical terminal constructions can be first attached to said one of said cups and then to the other of said cups.

16. A combination according to claim I in which said switch casing is formed by two insulative cups having oppositely directed rims, having cup bottoms forming said longitudinal sidewalls, having certain cup sides forming said transverse end walls, having other cup sides forming said bottom wall of said switch casing, and having other cup sides forming said cover wall of said switch casing.

17. A combination according to claim 16 in which said cups are held together by barbed member means which engage said cups with a holding action.

18. A combination according to claim 17 in which all three of said .electrical terminal constructions extend outwardly from at least one of said switch casin walls.

19. A combrnatlon according to c arm 18 m WhlCh all three of said electrical terminal constructions extend outwardly from only one of said casing walls.

20. A combination according to claim 19 in which all of said electrical terminal constructions extend outwardly from said cover wall.

Zl. A combination according to claim 20 in which all three of said terminal constructions extend outwardly from said cup sides forming said cover wall of said switch casing. 

1. In combination: an insulative switch casing having a bottom wall, longitudinal sidewalls, transverse end walls and a cover wall surrounding a relatively long and narrow switch cavity; upper and lower stationary blade stop members at one end of said cavity; a snap blade holding stationary member at the other end of said cavity and holding a stationary end of a snap blade which extends along said cavity and has a snap end between said stationary blade stop members; a gradually movable actuating blade with one end stationarily pivoted at said other end of said cavity and extending along said cavity with its free end adjacent said snap end of said snap blade; snap producing means at said free end and snap end of said blades causing a snap movement of said snap blade as said actuating blade free end is gradually moved back and forth; a vertically movable actuator actuatable from the outside of said cavity gradually moving an intermediate part of said actuating blade; a first electrical terminal construction extending from said snap blade holding stationary member to the outside of said switch casing; a second electrical terminal construction extending from said lower stationary stop member to the outside of said switch casing; a third electrical terminal construction extending from said upper stationary stop member to the outside of said switch casing; a first manual vertical adjusting member carried at one end of said switch casing vertically to adjust one of said stationary blade stop members; and a second manual adjusting member carried at the other end of said switch casing adjustably to impart a downward bias of an intermediate portion of said actuating blade against said actuator.
 2. A combination according to claim 1 in which said first and second electrical terminal constructions extend transversely of the length of said switch casing and said third electrical terminal construction extends longitudinally of the length of said switch casing.
 3. A combination according to claim 2 in which said electrical terminal constructions each includes an electrically conductive ribbon extending out of said switch casing.
 4. A combination according to claim 3 in which said third electrical terminal construction includes a relatively flexible electrically conductive ribbon connected to said upper stationary stop member at one end and to another relatively stiff electrically conductive ribbon extending out of said switch casing.
 5. A combination according to claim 1 in which a third manual adjusting member imparts an upward bias on an intermediate portion of said snap blade.
 6. A combination according to claim 5 in which said third manual member is a rotatable cam member which has an extension extending out of said switch casing.
 7. A combination according to claim 6 in which the snap blade has two ribbon members and the rotatable member has two cams carried on a shaft and engaging said ribbon members.
 8. A combination according to claim 7 in which said shaft has an extension Out of said switch casing and said extension is operated by an adjusting lever.
 9. A combination according to claim 1 in which said switch casing is formed by two insulative casing cups having respective adjoining rims, having cup bottoms forming said longitudinal sidewalls of said switch casing, having certain adjoining cup sides forming said transverse end walls of said switch casing, having other cup sides forming said bottom wall of said switch casing, and having other cup sides forming said cover wall of said switch casing.
 10. A combination according to claim 9 in which said cups are held together by barbed members which engage said cups with a holding action.
 11. A combination according to claim 10 in which at least one of said electrical terminal constructions has some of said barbed members.
 12. A combination according to claim 9 in which at least one of said terminal constructions includes at least one plate that extends into receiving slots in said cups.
 13. A construction according to claim 12 in which at least one of said plates has barbed members which engage said cups with a holding action.
 14. A combination according to claim 9 in which certain of the switch forming parts in said cavity can be first attached to one of said cups and then to the other of said cups.
 15. A combination according to claim 14 in which at least one of said electrical terminal constructions can be first attached to said one of said cups and then to the other of said cups.
 16. A combination according to claim 1 in which said switch casing is formed by two insulative cups having oppositely directed rims, having cup bottoms forming said longitudinal sidewalls, having certain cup sides forming said transverse end walls, having other cup sides forming said bottom wall of said switch casing, and having other cup sides forming said cover wall of said switch casing.
 17. A combination according to claim 16 in which said cups are held together by barbed member means which engage said cups with a holding action.
 18. A combination according to claim 17 in which all three of said electrical terminal constructions extend outwardly from at least one of said switch casing walls.
 19. A combination according to claim 18 in which all three of said electrical terminal constructions extend outwardly from only one of said casing walls.
 20. A combination according to claim 19 in which all of said electrical terminal constructions extend outwardly from said cover wall.
 21. A combination according to claim 20 in which all three of said terminal constructions extend outwardly from said cup sides forming said cover wall of said switch casing. 